1. College of Chemistry and Chemical Engineering, China University of Petroleum, Qingdao Shandong 266555, P.R.China;
2. College of Petroleum and Chemical Engineering, Liaoning Shihua University, Fushun Liaoning 113001, P.R.China;
3. College of Petroleum and Chemical Engineering, Shenyang University of Technology, Liaoyang Liaoning 111003, P.R.China